In vitro immunologic methods will be used to aid in the diagnosis and monitoring of patients with choroidal tumors. The clinical differentiation of choroidal mass lesions may be difficult. In those patients in whom the differential diagnosis is between a choroidal melanoma and a metastatic lesion, diagnostic assays such as fluorescein angiography and radioactive phosphorus uptake are often falsely positive. Immunologic factors appear to play an important role in the host-tumor interaction. We and others have demonstrated the existence of tumor-associated antigens in ocular melanomas. In preliminary work with a leukocyte migration inhibition (LMI) assay using a 3M KCl melanoma extract, we have observed good discrimination between patients with ocular melanomas and control subjects. Similarly the results of both the thermal stress erythrocyte rosette assay and lymphocyte stimulation with standard mitogens can be used to discriminate patients with choroidal melanomas from patients with metastatic choroidal lesions and benign choroidal diseases. We will observe whether in vitro immunologic response to standard and tumor-associated antigens will differentiate patients with ocular melanomas from patients with benign and metastatic simulating lesions better than conventional tests now in use. In addition to the problem of diagnosis, the correct management of choroidal melanomas is uncertain. Up to 45% of patients with ocular melanomas develop metastatic disease. Currently our methods of delineating those patients with a poorer prognosis are limited especially if "conservative therapy" is used rather than enucleation. Immune responses to standard and tumor-associated antigens and the presence of serum blocking factors have correlated with disease status and prognosis. All patients with choroidal melanoma will be serially tested to ascertain whether these immunological tests will be an indicator of early metastatic disease and hence be a better guide to prognosis than methods currently available.